The present invention relates generally to apparatus and methods for treating vascular conditions, and more specifically, to a wire guide for use in a body vessel.
Wire guides are commonly used in vascular procedures, such as angioplasty procedures, diagnostic and interventional procedures, percutaneous access procedures, and radiological and neurological procedures. In general, wire guides may be used to introduce a wide variety of medical devices into the vascular system.
For example, wire guides may be employed to treat atherosclerosis and other occlusive diseases, which are prevalent among a significant portion of the population. In such diseases, atherosclerotic plaque forms on the walls of the vessel and blocks or restricts blood flow through the vessel. Atherosclerosis commonly affects the coronary arteries, the aorta, the iliofemoral arteries and the carotid arteries. Several serious conditions may result from the restricted blood flow, such as ischemic events.
Various procedures are known for treating stenoses in the arterial or peripheral vasculature, such as the use of balloon angioplasty and stenting. During a balloon angioplasty procedure, a catheter having a deflated balloon attached thereto is positioned across a constricting lesion, and the balloon is then inflated to widen the lumen to partially or fully restore patency to the vessel. Stenting involves the insertion of a usually tubular member into a vessel, and may be used alone or in conjunction with an angioplasty procedure. Stents may be self-expanding or balloon expandable. Self-expanding stents typically are delivered into a vessel within a delivery sheath, which constrains the stent prior to deployment. When the delivery sheath is retracted, the stent is allowed to radially expand to its predetermined shape. If the stent is balloon expandable, the stent typically is loaded onto a balloon of a catheter, inserted into a vessel, and the balloon is inflated to radially expand the stent.
Wire guides also may be used in peripheral or arterial vessels for purposes other than occlusion treatment and stent deployment, such as delivering devices for providing embolic protection and retrieving foreign bodies. Generally, during each of the foregoing procedures, a wire guide is first inserted into a patient's vessel, e.g., under fluoroscopic guidance. The wire guide then is advanced toward a target site in the patient's vasculature. For example, the distal end of the wire guide may be advanced through a stenosis. Then, various medical components, such as a balloon catheter and/or stent, may be distally advanced over the wire guide to the target site.
Commercially available wire guides may comprise flexible distal regions in an effort to facilitate navigation through the tortuous anatomy of a patient's vasculature. For example, wire guides may employ a coil disposed to overlay a reduced diameter portion of core wire near the distal end of the wire guide. The coil may be adhered to the core wire using techniques such as soldering. One drawback associated with existing devices is that the solder may form a bumpy or inconsistent surface between the coil and the core wire. Moreover, the provision of solder may increase the overall profile of the wire guide in the vicinity of its attachment to the coil.
Where such wire guides having flexible distal regions are used, it also may be difficult to insert a medical component over the wire guide, for example, because the flexible distal region may be susceptible to kinking. However, if the distal region of the wire guide is too rigid, then it may not be sufficiently flexible to navigate the tortuous anatomy.
In view of the foregoing, there is a need for a guide wire suitable for navigating tortuous anatomy, permitting advancement of medical components, and having a reduced diameter profile and substantially smooth outer surface.